The flag isn't fluttering it is moving how a semi rigid body (eg thick plastic) wouldmove if you shake it.
In fact it proves it isn't in a fluid - when he moves it backward it is still curved in the same direction - so it can't be moving through anything with resistance.

Anyway, they wouldn't fake it in a water tank -they would use the same anti-gravity system from the Roswell spaceship that NASA uses to fake all it's space walks.

It's a bit of tape from the suit. It's not spherical and it appears to accelarate as it moves which means it is going toward the camera rather than straight up.

I assume you are looking for arguments to rebute the conspiracy claims?
If you were going to fake it you could do it all in CGI rather than a water tank.
A number of neighbouring countries watch this airspace for ballistic launch tracks - do you think there was no launch but USA, Japan, Russia, India, N. Korea are all part of some conspiracy to suppress that?

Staff: Mentor

It doesn't follow a straight trajectory the way a bit of tape would. It wants to go straight up and moves along the visor of the helmet until it is able to go straight up at the exact point a bubble would. The behavior is totally consistent with that of a bubble and inconsistent with that of a small object. Also, if it is a small piece of tape, what is the force that makes it start moving in zero-gravity? I can't identify any force making it move except what would make a bubble move in water.